A filling device of this type has become known from WO 96/06301. An anesthetic bottle is provided with a stationary outer tube and an inner tube, which is displaceable in such a way that it can perform a lifting motion and with which a bottle valve on the anesthetic bottle can be opened. A filling device at the anesthetic evaporator has a mounting hole for the outer tube and a stationary inner part, which can be brought into functional connection with the inner tube of the anesthetic bottle. A filling valve of the filling device, which valve is in connection with an anesthetic tank, has a valve plate, which can be lifted off from the valve seat by means of three pins, which point from the valve plate into the mounting hole.
When the anesthetic bottle is being introduced into the filling device, the outer tube will first touch the pins, as a result of which the valve plate of the filling valve is lifted off from the valve seat. The inner part will subsequently come into functional connection with the inner tube of the anesthetic bottle and the bottle valve of the anesthetic bottle opens. During the filling operation, the anesthetic bottle and the anesthetic tank are connected with one another in the form of communicating vessels via a fluid channel at the filling device, via which the liquid and gas exchange takes place.
When the anesthetic tank is filled with anesthetic to the maximum filling level, the filling operation ends due to the closure of the fluid channel, because no liquid or gas exchange is possible any longer between the anesthetic bottle and the anesthetic tank. It may happen now that a residual volume of anesthetic remains in the filling device and cannot flow off into the anesthetic tank any longer. Such residual volumes are problematic especially in case of anesthetics with low boiling points, because they escape directly into the environment after the removal of the anesthetic bottle from the filling device. A pressure, which is released abruptly when the anesthetic bottle is removed from the filling device after the filling, builds up during the filling in both the anesthetic tank and the anesthetic bottle because of the low boiling points of such anesthetics. Residual volumes of anesthetic that may have remained in the filling device may now be entrained to the outside.